High-voltage pulsing apparatus for a spark chamber



May 27, 1969 T. A'. ROMANOWSKI ET AL 3,447,032

HIGH-VOLTAGE PULSING APPARATUS FOR A SPARKCHAMBER Filed June 21. 1967 SOURCE ,8;

, I I i l2 VOLT/96E 5 v 7' P/ikk c/m/vam k zg LOGIC In mentors Thomas A Panza/mush I j Qfia/rles ,I fills/1 United States Patent US. (:1. 315-440 3 Claims ABSTRACT OF THE DISCLOSURE For a spark chamber embodying a plurality of spark chamber gaps defined by spatially mounted plate electrodes, a capacitor is provided for each spark chamber gap and has one side thereof connected through the cen- Contractual origin of the invention The invention described herein was made in the course of, or under, a contract with the United States Atomic Energy Commission.

Background of the invention This invention relates to plate-electrode-type chambers and more particularly to an apparatus for generating and applying a high-voltage pulse thereto.

Spark chambers are used to record nuclear events in the field of high-energy physics. The conventional plateelectrode-type spark chamber embodies a plurality of plate electrodes defining a plurality of spark chamber gaps. The plate electrodes are connected so that they are of alternate polarity, each alternate electrode being directly connected to a common electrical ground and the remaining electrodes being adapted to receive an applied highvoltage pulse. The conventional high-voltage pulsing apparatus for this spark chamber comprises a high-voltage source, a plurality of capacitors each connected from an associated ungrounded plate electrode of the spark chamber through a current-limiting resistor to the highvoltage source and a spark chamber trigger switch interconnected of the common junction of the capacitors and current-limiting resistors and electrical ground. It is appreciated that in this construction a single energy storage capacitor supplies two chamber gaps in parallel.

In operation, the high-voltage source charges each of the capacitors. Responsive to the spark chamber logic circuitry, the spark chamber trigger switch transfers the voltage of the capacitors to their associated plate electrodes, wherefrom an are results upon the passage of highenergy particles therethrough. It has been found that the time of firing for each of the chamber gaps is not always simultaneous and, if one chamber gap fires early, it is possible for it to discharge the associated storage capacitor, thereby resulting in either a faint spark or no spark at all in the other parallel chamber gap. The reduction of potential on the other parallel chamber gap due to premature discharge of the other chamber is termed robbing and is an undesirable characteristic of conventional highvoltage pulsing systems for spark chambers embodying plate electrode construction.

Accordingly, it is one object of the present invention to provide an improved apparatus for generating and ap- I 3,447,032 Patented May 27, 1969 "ice plying a high-voltage pulse to a spark chamber embodying plate electrode construction.

It is another object of the present invention to provide a pulsing apparatus for a spark chamber whereby an arc discharge responsive to a nuclear event is insured equally in each of the chamber gaps.

Other objects of the present invention will become more apparent as the detailed description proceeds.

Summary of the invention I The high-voltage pulsing apparatus for a spark chamber including spatially mounted plate electrodes defining spark chamber gaps therein comprises a plurality of capacitors equal in number to the spark chamber gaps of said spark chamber. A plurality of coaxial cables equal in number to said capacitors are provided. Means connect alternate ones of the plate electrodes through the center conductor of an associated one of the coaxial cables to an associated one of the capacitors. Means also connect the remainder of the plate electrodes to electrical ground through the outer conductor of associated ones of said coaxial cables. Means are provided for charging each of the capacitors to a predetermined voltage and for transferring the charge on the capacitors to said plate electrodes associated therewith.

Brief description of the drawing Further understanding of the present invention may best be obtained by consideration of the accompanying drawing wherein is shown a schematic representation of the preferred embodiment of an apparatus constructed according to the present invention.

Description of the preferred embodiment In the drawing, plate electrodes 10 and 12 define the spork chamber gaps 14 of a spark chamber. The plate electrodes 10 and 12 are connected so that they are of alternate polarity. For purposes of illustrtaion, plate electrodes 10 are connected to receive a positive potential high-voltage pulse and plate electrodes 12 are connected to be at electrical ground. A high-voltage source 16 has its output connected through a current-limiting resistor 18 to a plurality of like capacitors 20. The capacitors 20, equal in number to the gaps 14 of the spark chamber, are each connectedthrough the center conductor of an associated coaxial cable 22 to an associated positive plate electrode 10 of the spark chamber, as shown. A plurality of damping resistors 24 are each interconnected between electrical ground and an associated common terminal between the capacitors 20 and coaxial cables 22. The plate electrodes 12 are connected to electrical ground via the outer conductor of their associated coaxial cables 22, as shown. A spark gap trigger switch 26 is connected between electrical ground and the common terminal of the current-limiting resistor 18 and the capacitors 20.

In operation, the voltage source 16 charges each of the capacitors 20 through the current-limiting resistor 18. Responsive to the spark chamber logic circuitry 28, the spark gap trigger switch 26 closes and the voltage across each of the capacitors 20 is thereby impressed across their associated spark chamber gap 14, wherefrom an arc will result upon the passage of high-energy particles therethrough. The damping resistors 24 provide a current path for the discharge of the charged capacitors 20 if the chamber gaps 14 do not fire and also provide a charging path for recharging of the capacitors 20.

With the aforedescribed construction, it has been found that the chamber gaps 14 discharge uniformly with little or no robbing between adjacent parallel gaps. It will be noted that from this construction each of the chamber gaps 14 embody their own charging capacitor 20 and are decoupled from their adjacent parallel gap 14 via the coaxial cables 22. Thus, the chamber gaps 14 are individually charged from capacitors 20 through the coaxial cables 22 and the robbing path, if any, for the chamber gaps 14 is through the outer conductor of the coaxial cables 22, a high-inductance path. The chamber gaps 14 therefore have identical charging paths and discharge With minimum robbing effect.

The following size construction has been found satisfactory for a spark chamber embodying plates 10 and 12 sized 80" x 70" with a 280-mil. effective spark chamber gap 14 therebetwecn.

Coaxial cables 20 Each 6' in length. Type RG59/U coaxial cable. Capacitors 20 4000 picofarads each. Damping resistors 24 50 ohms each. Charging voltage from source 16 10,000 volts.

Persons skilled in the art will, of course, readily adapt the general teachings of the invention to embodiments far different than the embodiment illustrated. Accordingly, the scope of the protection afforded the invention should not be limited to the particular embodiment illustrated in the drawing and described above, but should be determined only in accordance with the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A high-voltage pulsing apparatus for a spark chamber including spatially mounted plate electrodes defining spark chamber gaps therein comprising a plurality of capacitors equal in number to the spark chamber gaps of said spark chamber, a plurality of coaxial cables equal in number to said capacitors, means for connecting alternate ones of said plate electrodes through the center conductor of an associated one of said coaxial cables to an associated one of said capacitors, means for connecting the remainder of said plate electrodes to electrical ground through the outer conductor of associated ones of said coaxial cables for charging each of said capacitors to a predetermined voltage, and means for transferring the charge on said capacitors to said plate electrodes associated therewith.

2. The apparatus of claim 1 wherein said coaxial cables are alike, said capacitors are alike, and further including a plurality of like impedances equal in number to said capacitors, each of said impedances being interconnected of electrical ground and an associated common terminal of said capacitors and said center conductors of said coaxial cables.

3. A high-voltage pulsing apparatus for a spark chamber including a triad of spatially mounted plate electrodes defining a pair of spark chamber gaps comprising a pair of capacitors having one side thereof in common electrical connection, a pair of coaxial cables, means for connecting the other side of each of said capacitors through an associated center conductor of said coaxial cables to an associated one of said plate electrodes, means for connecting the other of said plate electrodes to electrical ground through the outer conductor of associated ones of said coaxial cable, means for charging said capacitors, and means for connecting the electrically common side of said capacitors to electrical ground whereby the charge thereon is transferred to the associated plate electrodes of said spark chamber.

US. Cl. X.R. 

